Field of the Invention
The present invention relates to an ink, an ink cartridge, and an image recording method.
Description of the Related Art
An inkjet recording method is one of the image recording methods that have been significantly developing in recent years because a high-quality color image can be easily recorded by the method despite the fact that its principle is simple. In addition, the method has rapidly become widespread not only in the image recording of a document, a photograph, and the like in households that has heretofore been mainstream but also in offices and industrial applications.
Various ink compositions have heretofore been investigated for the purpose of increasing the optical density of an image to be recorded on a recording medium, such as plain paper. For example, there has been proposed an ink obtained by blending a self-dispersion pigment having bonded thereto a functional group having a high calcium index value and a dispersion liquid of a polyurethane prepolymer, the ink being capable of recording an image having satisfactory color developability (Japanese Patent Application Laid-Open No. 2013-535548).